re: Do you think JFK was murdered by the government?

I've read a theory that one of the guys in the car behind JFK had an AR15 rifle. He can be seen in the pics of the event.

He's seen standing with it. The theory goes that as he was standing, the car accelerated. He started to fall and when he did, it squeezed off a round. That round went into the back of JFK's head making it basically explode.

That's why he had a smaller diameter hole in his skull than the carcano ammo would make. The diameter of the 5.56mm round was smaller.

I also read That's why his brain vanished. It would have had 5.56 round fragments in it. Early production barrels had a low twist rate and bullets used to yaw upon entry and come apart.